Minimally Invasive Transpedicular Screw Fixation: Review of 152 Cases in a Single Institution. Steep or Shallow Learning Curve?

BACKGROUND: In this study, we analyze our institutional experience and personal impressions using minimally invasive spine surgery (MISS) to describe our learning curve and how experience influenced different parameters of the surgical procedure. METHODS: The study was conducted prospectively and included the first consecutive 152 patients treated with MISS techniques. Patient demographics, surgical data, length of hospital stay, and clinical outcome were reviewed. The cohort was divided into consecutive quarters. Comparison between the quarters and timeline analysis were made to assess the learning curve. RESULTS: Only percutaneous transpedicular screw fixation was performed in 65 cases, minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) in 70 cases, and vertebral body replacement in 4 cases. The average blood loss was 113.3, 115, 106.6, and 107.1 mL for each quarter. The average operative time was 155.0, 143.2, 134.5, and 133.8 minutes for the four quarters, whereas the average radiation exposure time was 105.4, 85.3, 46.2, and 45.2 seconds. Differences in the operative time and radiation exposure time between the first to third and the first to fourth quarters were statistically significant. CONCLUSIONS: Some advantages of MISS techniques could be observed with the very first cases and were not related significantly with the surgeon's experience with MISS. With the acquisition of more experience, some disadvantages of MISS techniques such as longer operative time and longer X-ray exposure can be substantially reduced. Surgical experience, familiarity of the team with the MISS instrumentation, and good patient selection are crucial for achieving all the benefits of MISS.

Impact of surgical treatment on the performance status of patients with high-grade gliomas.

OBJECTIVES: The objective of our study is to evaluate the impact of neurosurgical operative treatment on the performance status assessed by the Karnofsky Performance Scale (KPS) in patients with HGG for the first, for the second intervention and for the different age groups. METHODS: A group of 425 patients operated consecutively for high-grade gliomas were included in this study. The performance status was evaluated preoperatively and 15 days postoperatively with the KPS. Analyses for the different histological grade, tumor locations and age groups divided by decades have been made. RESULTS: The initial, preoperative KPS score for patients with grade III tumor was 77.65 and for grade IV - 71.35. Following the first operation mean KPS has a statistically significant increase and reaches 82.24 and 78.41, respectively. The improvement of the performance status after the first operation was significant for all relevant age groups, including the sixth, seventh and eighth decades. Although the obtained mean KPS scores after the second operation did not show improvement there was also no clear evidence for worsening in this group of patients (n = 100) and the negative results obtained were not statistically significant. CONCLUSION: According to our study, the first operation has a beneficial effect on the performance status in patients with HGG. The results for the second operation are more ambiguous, but there is no clear evidence for worsening of the KPS score after the second intervention. These results were relevant for all age groups, so we may expect amelioration in the performance status even in older patients.

Delayed intraventricular hemorrhage in moderate-to-severe traumatic brain injury: prevalence, associated risk factors, and prognosis.

BACKGROUND: The presence of traumatic intraventricular hemorrhage (tIVH) on an admission CT scan is related to a worse outcome and increased mortality in patients with moderate and severe TBI. Currently, there is no available data regarding the predictive value of the appearance of tIVH as a delayed finding on follow-up CT scan. The purpose of this study was to determine the prevalence, associated risk factors, and prognosis of delayed tIVH. METHODS: The study is based on 401 consecutive adult patients (age ≥ 18 years) with moderate-to-severe TBI admitted in our hospital for a 5-year period. At least one control CT was performed in 320 (79.8 %) patients. The prevalence of delayed tIVH was assessed and the potential risk factors and mortality were analyzed. RESULTS: Delayed tIVH appeared in 38 cases (11.9 % of the second CT scans and 9.5 % of all patients). The patients with delayed tIVH are significantly older (57.39 vs. 48.63 years, p = 0.009) and developed statistically significant more frequent enlargement of an existing lesion (47.4 vs. 20.2 %, p = 0.001) and appearance of a new lesion (100 vs. 33.7 %, p < 0.001). Delayed tIVH appeared significantly more frequent in surgically treated patients with ICH as a main surgical lesion (p = 0.010) and is associated with significantly higher mortality (p < 0.001). CONCLUSIONS: Delayed tIVH as a progression of injury in moderate-to-severe TBI has a relatively high occurrence and is associated with increased mortality. The only factor independently related to a new appearance of tIVH is the presence of ICH as a main surgical lesion on the control preoperative CT scans.

The premamillary artery--a microanatomical study.

BACKGROUND: The microanatomical parameters of the premamillary artery (PMA) for the different configurations of the posterior communicating artery-adult (aPComA), hypoplastic (hPComA) and foetal (fPComA) were assessed and analysed. A comparative study with relevance to the neurosurgical practice has been carried out. METHOD: Red-coloured latex was injected in 35 human cadaver brains and a microanatomical dissection was performed. The area of emergence, the diameter, the length and the zone of penetration of the PMA were accessed. RESULTS: Seventy PComA were found and 96 PMA were identified. In more than 85% of the cases, the diameter of the PMA largely surpassed the diameter of the other perforating vessels. In the aPComA group, the PMA was a single branch in 72.4% of the cases with mean diameter of 0.52 mm and average length of 13.22 mm. PMA was found to originate from the middle third in 60.5%. For the hPComA group, in 66.7% of the cases, one PMA with mean diameter of 0.49 mm and average length 12.41 mm was found. In 60.9%, PMA originated from the middle third. For the fPComA group, in 50.0% of the cases, one PMA was found with mean diameter of 0.39 mm, average length of 12.42 mm. PMA was found to originate from the anterior third in 41.7% of the cases. Emergence of the PMA from the internal carotid artery and from the P2 segment of the posterior cerebral artery was also documented. CONCLUSION: For the aPComA and the hPComA groups, the typical PMA may be described as the largest and most constant perforating branch emerging from the anterior 2/3 of the PComA and reaching the paramedian perforate substance. The PMA of the fPComA generally conforms to these characteristics but it is usually thinner, frequently duplicated and with higher percent of atypical emergence. These anatomical peculiarities may facilitate the intraoperative identification and preservation of the PMA when dealing with vascular or neoplastic pathologies with parasellar or interpeduncular extension.